1. Field of the Invention
The present invention relates to a stereoscopic display capable of viewing a stereoscopic image without using special glasses.
2. Description of the Prior Art
As a method of realizing display of a stereoscopic image without requiring special glasses, a method of a double lenticular system using two liquid crystal display (LCD) projectors as well as using a double lenticular screen as a screen has been proposed. This system is a system of respectively displaying a left eye image and a right eye image from one LCD projector 1a and the other LCD projector 1b, and projecting the images on a double lenticular screen 200 arranged ahead of the projectors, as shown in FIG. 10. The double lenticular screen 200 is so constructed that lenticular screens 200a and 200c are arranged ahead of and behind a dispersion panel 200b on which the images are formed such that the dispersion panel 200b is interposed therebetween.
The left eye image and the right eye image are respectively changed into vertically striped images 200bL and 200bR by the function of the lenticular screen 200a on the side of the LCD projectors 1a and 1b (on the incidence side), and are alternately formed on the dispersion panel 200b. The right eye striped image and the left eye striped image out of the vertically striped images formed on the dispersion panel 200b are introduced upon being respectively separated into the right eye (3R) and the left eye (3L) of a viewer 3 by the function of the lenticular screen 200c arranged on the light emission side of the dispersion panel 200b (on the side of the viewer). The viewer who views the left and right eye striped images with his or her respective eyes can view a stereoscopic image without wearing special glasses by the function of binocular parallax.
In this type of stereoscopic display, regions where a right eye image or a left eye image can be viewed alternately exist at the optimum viewing distance (D) from a screen 200, as shown in FIG. 11. In FIG. 11, a range indicated by an arrow R is a right eye image viewing region, and a region indicated by an arrow L is a left eye image viewing region. When the right eye 3R and the left eye 3L of the viewer 3 are respectively in the R region and the L region (a position indicated by A), a stereoscopic image can be viewed. On the other hand, in the reverse case (a position indicated by B), a stereoscopic image cannot be viewed due to reversed view.
As a method of preventing a reversed view state created by the shift in the position of the head of the viewer, a method of detecting the position of the head of a viewer 3 by a sensor 100 for detecting the position of the head of the viewer 3, and replacing the right and left images displayed by the LCD projectors 1a and 1b (which are not illustrated in FIGS. 12 and 13) when it is judged that the head of the viewer 3 is in a reversed viewing position, for example, has been conventionally known, as shown in FIGS. 12 and 13. That is, when the position of the viewer 3 is changed from a just image viewing position as shown in FIG. 12 to a reversed viewing position, the right and left eye images displayed are replaced with each other, as shown in FIG. 13. Consequently, an image viewing region R indicated by a rhombus is positioned in the position of the right eye of the viewer, and an image viewing region L indicated by a rhombus is positioned in the position of the left eye of the viewer.
In the above-mentioned prior art, however, means for replacing the right and left images with each other is required. A large screen display is viewed by a plurality of viewers in many cases. In this case, when only one of the viewers moves, and the right and left images are replaced with each other by its head tracking, the other viewers in just image viewing positions cannot view a proper image.
The present invention has been made in view of the above-mentioned circumstances, and has for its object to provide a stereoscopic display requiring no means for replacing right and left images with each other and capable of properly viewing, even when it is viewed by a lot of viewers, a stereoscopic image by each of the viewers.